科学美国人60秒 SSS Stopping Splashes with Smarter Surfaces
时间：2018-12-24 作者：英语课 分类：2016年Scientific American(十二)月
When you spill a liquid on the ground, it splashes. But if you’re a guy using a urinal, or, more important, if the liquid is dangerous, say, an infected blood sample, you want to limit splashing. In other words:
“If an accident happens, you want the drop to fall onto the surface and that’s it. It just stays there as a single body.”
Alfonso Castrejo?n-Pita, an engineering professor at Oxford 1 University.
“So you could imagine the situation of having your [lab] bench covered with these kinds of materials so they become safer. And the same for a kitchen. Now you’re in a kitchen, you are handling raw chicken, and the last thing you want is to have splashes, where you could be transmitting salmonella or these kinds of ugly things that you could get when you are handling raw meat.”
He and his colleagues found that the softer the surface the smaller the splash. Their study is in the journal Physical Review Letters. [Christopher J. Howland et al., It’s Harder to Splash on Soft Solids]
The researchers prepared a bunch of increasingly squishy silicone surfaces and released drops of ethanol onto them from different heights. They captured video of the splashes with a super-slow-motion camera that records more than 100,000 frames per second. And they found that the drops eventually stopped splashing on the softest surfaces.
So far that all sounds predictable. But computer models of the splashes revealed interesting details.
At the moment the blob of liquid makes contact with the surface, the bottom of the drop flattens 2 out and the pressure increases. The ring of pressure spreads towards the drop’s edges. If the surface is too hard, the ring of high pressure creates tiny droplets 3 that explode from the main drop’s edges. But the softest surfaces deform 4 in response to the drop hitting them—and that prevents the pressure from getting high enough to cause that explosion.
Sadly, you won’t see squishy coatings on urinals just yet, or in your laboratories—anti-splash materials are too frail 5.
“The softest ones are quite delicate so you wouldn’t be able to make a laboratory bench with them, they’d get damaged quite quickly.”
So we’d need soft coating materials robust 6 enough to withstand daily wear before the splash is relegated 7 to history’s trash bin…or toilet.
—Ryan Mandelbaum
- At present he has become a Professor of Chemistry at Oxford.他现在已是牛津大学的化学教授了。
- This is where the road to Oxford joins the road to London.这是去牛津的路与去伦敦的路的汇合处。
- After Oxford the countryside flattens out. 过了牛津以远乡村逐渐平坦。
- The graph flattens out gradually after a steep fall. 图表上的曲线突降之后逐渐趋于平稳。
- Droplets of sweat were welling up on his forehead. 他额头上冒出了滴滴汗珠。 来自辞典例句
- In constrast, exhaled smoke contains relatively large water droplets and appears white. 相反，从人嘴里呼出的烟则包含相当大的水滴，所以呈白色。 来自辞典例句
- Shoes that are too tight deform the feet.(穿)太紧的鞋子会使脚变形。
- Ice crystals begin to deform measurably.冰晶就产生某种程度的变形了。
- Mrs. Warner is already 96 and too frail to live by herself.华纳太太已经九十六岁了，身体虚弱，不便独居。
- She lay in bed looking particularly frail.她躺在床上，看上去特别虚弱。